Bump actions/upload-artifact from 6 to 7

Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 6 to 7.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](actions/upload-artifact@v6...v7)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: '7'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

.github/workflows/ci.yml

@@ -37,7 +37,7 @@ jobs:
       run: sbt -v compileDocumentation
     - name: Test
       run: sbt -v test
-    - uses: actions/upload-artifact@v6  # upload test results
+    - uses: actions/upload-artifact@v7  # upload test results
       if: success() || failure()        # run this step even if previous step failed
       with:
         name: 'tests-results-java-21'